Rule #4 under "2.3.2.1 Predicates" in both the XQuery 1.0 and XPath 2.0
documents seems needlessly awkward to me. The rule states,
4) "If the value of the predicate expression is a sequence that contains at
least one node and does not contain any item that is not a node, ..."
Rule #1) states, "If the value of the predicate expression is an empty
sequence, ...". Thus if we've gotten as far as #4, we already know we have a
non-empty sequence. So why not simply say something as straightforward as,
4) "If the value of the predicate expression is a purely homogeneous
sequence of nodes only, ..." or some such? I don't see any loss of technical
accuracy by doing so.
Best,
Howard